help?LSAT Section2-II-11

bigmouse

11. “If the forest continues to disappear at its present pace, the koala will approach extinction,” said the biologist.
“So all that is needed to save the koala is to stop deforestation,” said the politician.
Which one of the following statements is consistent with the biologist’s claim but not with the politician’s claim?
(A) Deforestation continues and the koala becomes extinct.
(B) Deforestation is stopped and the koala becomes extinct.
(C) Reforestation begins and the koala survives.
(D) Deforestation is slowed and the koala survives.
(E) Deforestation is slowed and the koala approaches extinction.
answer:B my choice

merlion

AA:forest continues to disappear
BB:koala will approach extinction

biologist:AA->BB
politician:非AA->非BB

in the answer (B), BB 和 非AA.  非AA可以->非BB, 而（b）中是BB, 反politician. BB 和 非AA对biologist来讲，不能推出什么，so consistent

bigmouse

谢谢你的解答，不过好像还是不太明白？

qiqi_cola

我也没明白2楼的解释，哪位再来解释一下？

mindfree

It is pure logic.

B: Deforestation is the sufficient condition to K's extinction (Def-->Ext)
P: Deforestation is required condition for extinction (Not Def-->Not Ext) (I do not think it is also a sufficient condition in P's claim)

Now you should be able to understand the answer.

bigmouse

呵呵，这样解释好像更合理一些！谢谢！

merlion

本想可以帮帮别人的， 没想到...

anyway, thanks god Mindfree helps make it clear.

bigmouse

以下是引用merlion在2003-9-6 11:11:00的发言：
本想可以帮帮别人的， 没想到...

anyway, thanks god Mindfree helps make it clear.

呵呵，你也很好啊！

运河

苦思不解，一读受益，感谢bigmouse和merlion。